Machine vision systems (also simply termed “vision systems”) use image acquisition devices that include camera sensors to deliver information on a viewed subject. The system then interprets this information according to a variety of algorithms to perform a programmed decision-making and/or identification function. An image of an object containing features of interest to the system is acquired by an on-board image sensor (also termed, simply an “imager” or “sensor”) in the visible, and/or near-visible light range under appropriate illumination, which can be based upon ambient light, and/or light provided by an internal and/or external illuminator.
A common task for vision systems is the reading and decoding of symbology (e.g. one-dimensional and two-dimensional codes—also termed “IDs”) used in a wide range of applications and industries and can take the form of 1D barcodes, 2D DataMatrix Codes, QR Codes and DotCodes, among others. The image sensor acquires images (typically grayscale or color, and in one, two or three dimensions) of the subject or object, and processes these acquired images using an on-board or interconnected vision system processor. The processor often includes both processing hardware and non-transitory computer-readable program instructions (software) that perform one or more vision system processes to generate a desired output based upon the image's processed information. This image information is typically provided within an array of image pixels each having various colors and/or intensities. In the example of an ID reader (also termed herein, a “camera”), the user or an automated process acquires an image of an object that is believed to contain one or more barcodes, 2D codes or other ID types. The image is processed to identify encoded features, which are then decoded by a decoding process and/or processor to obtain the inherent alphanumeric data represented by the code.
A common form of ID reader used in industrial (and other commercial) applications is the handheld ID reader. This type of reader typically includes a grip that enables the user to carry the reader around a floor space and aim the device at various objects. The grip is provided with one or more trigger buttons that allow the user to direct the acquisition of an image of an object containing an ID after it is aimed at that object. This acquired image is then decoded and the information is transmitted (typically wirelessly) to a receiving unit. The receiving unit transfers the information to another data-handling system, such as an inventory tracking or logistics application running on a server or other computing device (e.g. a PC).
Typical contemporary handheld ID readers include a rechargeable battery and a plurality of charging and data contacts that removably engage with corresponding contacts on a base unit. The base unit is interconnected with a power source, such as wall current, and can include various data connections (e.g. USB, Ethernet, etc.) that enable the base unit to act as a wireless receiver for code data transmitted from the handheld ID reader. Such data is collected by the base unit and forwarded via the data connection to the data handling system. Alternatively, a separate wireless receiver operatively connected to the data handling system can be employed.
Most conventional base units (for example, those available from Honeywell or Motorola) use electrical spring contacts to removably connect with the handheld ID reader. A common disadvantage of such arrangements is that their contacts wear out and/or can be damaged easily. Thus, precise insertion of the reader into the base unit is required, and it proves difficult to maintain a reliable contact due to close tolerances, contamination and insufficient pressure by the reader's contact pads on the base unit's contacts.